Process for making non-woven fabric



Aprll ll, 1961 R. G. TURNER PRocEss FOR MAKING NoN-WOVEN FABRIC FiledJune 13, 1958 FIG. 2

INVENToR RICHARD G. TURNER l @ma ATTORNEY United States Patent PROCESSFUR MAKING NON-WOVEN FABRIC Richard G. Turner, Worcester, Mass.,assignor to Crompton & Knowles Corporation, Worcester, Mass., acorporation of Massachusetts Filed June 13, '1958, Ser. No. 741,860

3 Claims. (Cl. Ztl-72.2)

This invention relates to improvements in nonwoven fabrics and to themethod and apparatus for their manufacture.

Many forms of so-called nonwoven fabrics which are made directly from aweb of loosely assembled bers include binders of one form or anotherwhich tend to strengthen the fabric but also prevent it from havingdesirable flexibility and draping qualities. It is an important objectof the present invention to reenforce a web of bers by interconnectinggroups of bers in a manner to provide areas of increased strength whichmake an adhesive binder unnecessary. This result as shown hereininvolves the step of forming the ber groups into loops and interloopingthem in a manner similar to the knitting process but differing from thelatter in that the groups of bers are not in the form of completedthreads or yarns but are rooted in the web and are frictionally engagedwith other bers of the web.

lt is a further object of the invention to provide a nonwoven fabric ofthe general type mentioned wherein interconnecting loops formed fromgroups of bers are disposed on one side of the web to give it a knittedappearance while the opposite side of the web has its bers unlooped andpossesses a fleece-like texture.

It is another object of the invention to provide a method for formingthe loops including the use of a knitting needle which is projectedpartway into the web to engage a small number of bers and then bewithdrawn to hold these bers in the hooked end of the needle to form aloop through which the needle can draw the next group of bers which itcollects from the web. In this method the fibers which are formed inloops may extend through to the other side of the fabric or may befrictionally entangled or engaged with other fibers of the web so thatwhile the loops are fairly well pronounced on one -side of the fabricthe bers of which they are formed extend in diverse directions into theweb without producing a pattern on the opposite side.

lt is another object of the invention to provide means whereby the sizeof the group of bers being caught by the hook of the needle can bevaried. In this feature of the invention the needle is inserted partwayinto the web along one path and is then depressed to be withdrawn alonga different path, the amount of depression of a needle depending uponthe number of fibers which are desired to form the loop.

It is a further object of the invention to provide for holding the webdown at the sides of a needle so that when the latter is withdrawn itwill not be able to lift the entire web.

It is a still further object of the invention to provide for holdingdown the bers which are just beyond and aligned with the hook of theneedle to prevent undesired lifting `of unhooked bers by neighboringhooked bers as the needle is withdrawn. In this feature of the inventionthe pressing down force is exerted more or less in a line with theneedle as distinguished from the first holddown forces which are exertedat the sides of the needle.

It is another object of the invention to provide a machine by which thefabric can be made. The machine includes a bar to carry a series ofneedles together with means to move the bar so that the needles will beinserted into and withdrawn from the web. TheI machine also includes afeed for the web whereby the latter is moved progressively through themachine to and away from the operating zone at which the needles operatewhile forming the aforesaid loops. The machine also is so rnade that itcan vary the amount by which the needle is depressed to vary the size ofthe group of fibers which are to be withdrawn from the web and means arealso provided for varying the amount of downward force exerted on theparts of the web in alignment with the needles.

It is another object of the invention to provide a fabric and the methodof making it wherein two webs are moved into face to face contact and'are joined by interconnected loops which form wales that are buriedwithin the fabric so that both sides of the latter will have afleecelike structure.

In order that the invention may be clearly understood reference is madeto the accompanying drawings which illustrate by way of example thethree embodiments of the invention and in which:

Fig. l is a plan view of a fabric made according to the preferred formof the invention showing several wales of interknitted loops of bers,

Fig. 2 is an enlargement of a part of Fig. l showing in greater detailthe looping of the groups of bers and the manner in which the fibers ofthe group are distributed into the web,

Figs. 3 and 4 are vertical sections on line 3-3 and 4 4 respectively,Fig. 2,

Fig. 5 is an end view looking in the direction of arrow 5, Fig. 1,

Fig. 6 is a View similar to Fig. 5 but sho-wing a modified form of theinvention wherein the wales of interconnected loops are formed on bothsides of the fabric,

Fig. 7 is a diagrammatic view of a machine for making fabric accordingto the invention,

Fig. S is a detail side view looking in the direction of arrow 8, Fig.7,

Fig. 9 is a diagram showing a needle which has just been inserted into aweb and the means for holding down the adjacent bers,

Fig. l0 is a diagram showing drive connections between the cam shaft andweb advancing roll shown in Fig. 7, and

Fig. 1l is a diagram showing a modified form wherein two webs are joinedby interconnecting loops arranged along the contacting faces of thewebs.

The raw material from which the fabric is made cornprises a web built upof a large number of loosely assembled fibers which may be made in anymanner as for instance in a carding machine. The fabric F1 shown in Fig.l is made from such a web but has a series of parallel wales 1 ofinterconnected loops running lengthwise of the web. These wales may beas close or as far apart as the pattern of the particular fabricrequires. As shown in Fig. 5 the wales are all on the top side of thefabric, the fibers below the wales being substantially in their originalform and having a fleece-like texture, many of these fibers, however,being drawn into the loops which form the wales.

Referring more particularly to Fig. 2, three loops 2, 3 and 4 are shownas representing a small fragment of the structure shown in Fig. l. Theloop 2- has drawn up through it loop 3, and in turn the latter has drawnfor-rn, the fibers at each side of each of the loops 2, 3 and 4spreading out at 6 and being rooted down into the web. Fig. 4 shows theupper part of loop 3 over the widened part of loop 2.

Fig. 6 shows a modicationwhich is somewhat similar to the fabric shownin Fig. l except that there is a series of wales 7 on the undersidethereof as well as on the top, the wales on the underside beingpreferably staggered transversely with respect to the-wales on the topside. The fabric lF2 shown in Fig. 6 can be made by running the webthrough a machine as will be described to form rst a series of wales onone side of the web after which the web is inverted and, if desired,passed through the machine a second time in reversed order to form aseries of wales on the opposite side.

In the usual knitted fabric the breaking of a thread will result in aso-called run in which a number of loops become disconnected. In thepresent invention the breaking of a loop will not result in a similarrun due to the fact that the groups of bers are anchored or rooted intothe web. When making the fabric shown in Fig. 6 by running the fabricthrough the machine in reversed. order the loops of the wales on oneside will be pointed or directed in a direction opposite the directionof the loops in the wales on the opposite side, thereby furtherpreventing runs which would otherwise produce a thin spot in the fabricF2.

Referring more particularly to Figs. 7, 8 and l0, the machine has aframe 10 provided with a xed table 11 over which runs a conveyor lbelt12 trained around right and left-hand pulleys 13 and 14. The web W issupplied from the left as viewed in Fig. 7 and is deposited on the belt12 and is moved toward the right and after the knitting oper-ation hasbeen performed producing the fabric F1, the latter is led to anyappropriate form of wind-up mechanism 15.

Mounted for oscillation on frame part 21 on each side of the machine isa needle guide having parallel guide plates 22 and 23. A needle bar onblock 24 extends across the machine and has each of its ends receivedbetween plates 22 and 23. It is to be understood that the guides 20 rockin unison `and that by their angular position they determine the angleof motion of bar 24.

The bar 24 has secured thereto a number of aligned transversely spacedneedles N which are very similar to a well-known type of knittingneedle. These needles project away from the bar 24 in an inclineddownward position as shown in Fig. 7 and the position of the needles isdetermined by the location of the bar 24 in the guides 22 and 23.

In order to cause sliding of the bar 24 along its guides 22 and 23 thereis provided a shaft 25 which has secured thereto a relatively largebevel gear 26 driven by motor M by means of a smaller bevel pinion 27. Acrank pin 28 on each of two cam plates 29 secured to shaft 25 isconnected to one end of a link 30 the other end of which is pivotallyconnected at 31 to an end of bar 24. It is to be understood that thereis a link 30 and a cam plate 29 at each side of the machine so thatreciprocating motion may be given to the opposite ends of the bar 24 asthe shaft 25 rotates.

At each side of the machine is a lever 35 pivoted at 36 to frame part 21having rotatable thereon a roll 37 which engages the adjacent cam 29.The upper end of each lever 35 is formed with a slot 38 in which isadjustably secured a stud 39 on which is pivoted the righthand end of alink 40 as viewed in Fig. 7. The link has its left-hand end pivoted tothe stud 41 which lis adjustable in a slot 42 formed in an arm 43projecting upwardly from the adjacent guide 20. It is by means of cams29, levers 35, links 40 and studs 41 that the needle carrier or guides20 can be rocked angularly with respect to the machine frame.

Asystem of gearing G interconnects the shaft 25 and shaft 45 to whichthe roll 13 is secured. This system G 4, effects a considerablereduction in speed so that the shaft 45 will rotate at a low ratecompared to the speed of shaft 25. The roll 13 will advance only afraction of an inch for each rotation of the shaft 25 and the belt 12will be relied upon to turn the roll 14. The web is therefore fedthrough the machine at a uniform rate which, however, is slow enough topermit insertion and withdrawal of the needles N into the web as theshaft 25 rotates.

Other frame parts 49 have mounted for rotation thereon a shaft 50 havingsecured thereto a number of spaced discs 51 which are at the sides ofthe needles so that the latter project into the spaces between thediscs, see Fig. 8. These discs serve to limit upward motion of that partof the web adjacent to the needles or at the operating Zone and arerotated so as to have a peripheral speed equal to the linear speed ofthe web. Rotation of the discs is effected by pulleys 52 and 53 securedto shafts 45 and 50 respectively and connected by a crossed belt 54. Thediscs therefore rotate in a direction to assist in feeding the web tothe right as viewed in Fig. 7 as the belt 12 moves in the directionindicated by arrow a.

Mounted for oscillation on the frame parts 49 is still another shaft 60to which are secured arms 61 each having a radial slot 62 in which isxed in adjusted position a stud 63 on which is pivoted the left end of alink 64. The right-hand ends of the latter links may be pivoted on studs41 or another stud similar to it.

Secured to the shaft 60 is a push-down structure 65 from which extenddownwardly into spaces between the discs a series of placer feet 66.These feet are aligned with the needles and terminate close to thelatter when the needles are fully inserted into the web. The feet aremountedA for slight rising and falling motion and are intended to be inlow position when the needle is being withdrawn after which the feet canbe lifted to remove any frictional obstruction which they mightotherwise offer to onward feed of the web. The undersides of the feetwill, of course, be smooth so that the web can slide under them andwhile the feet have been shown as capable of having a slight motiontoward and from the web they can, if desired, be left in xed downposition and not rocked.

In operation the needle bar 24 will be reciprocated along the slides 22and 23 and `as the needles move downwardly toward the web their hooks 70will be exposed and will be partially inserted into the web `as bar 24reaches the limit of its lefthand motion, Fig. 7. The hooks are roundedas shown in Fig. 9 and any ofthe fibers which engage the underside ofthe hook will be pressed down so that they cannot be caught by the hookwhen the latter -is withdrawn. The fibers engaging the upper part of thehook, however, may be somewhat deilected by the hook and as the latterpasses the deflected fibers they will tend to move back into the path ofthe hook. When the needles are withdrawn the fibers in the paths oftheir hooks will be lifted and be collected into groups, Vas alreadydescribed.

If the needle is not pushed down after being inserted Y into the web asshown in Fig. 9 but is withdrawn along the-same path of its insertionthen all of the bers which are in the path of the hook as shown in Fig.9 will be pulled up to form groups. This condition could exist bydisconnecting a mechanism which rocks thefneedle carrier or guides 20and fixing the latter` in position. If, however, it is desired that alesser amount of bers than that indicated in Fig. 9 be lifted by thehooks the latter will then be rocked in a downwardly direction beforebeing withdrawn. This downward rocking is effected by a decline 71 oneach cam 29 which comes under its roll 37 when the needles have reachedtheir lowest position so that a slight further turning of shaft 25 willallow springs 72 to rock the carrier 26 and depress the hooked ends ofthe needles. The bar 244 is then withdrawn so that the needlesare-pulled out of the web" along the path somewhat lower than the paththey traveled when being inserted into the web. The hooks 70 thereforewithdraw a reduced number of fiber to make a smaller group and loop.After the needles have been fully withdrawn and the shaft 25 given ahalf turn from the position shown in Fig. 7 an incline 73 on each cam 29will engage its roll 37 to rock carriers 20 in a clockwise direction andthereby lift the needles for their next inserting motion.

As the hooks of the needles are withdrawn from the web they tend to liftthe fibers engaged by them and in doing so may tendto lift the wholearea across the web at the operating zone. The discs 51, however, exertdownward forces on the web so that only those pants of the web betweendiscs can be lifted by the needles. Also, the feet 66 exert downwardforces on those parts of the web intermediate the discs but aligned withthe needles so lthat the lifting eect of the hooks as the needles arewithdrawn is limited lto a small area between the discs and to the rightof feet 66, Fig. 7.

The needles N as shown herein are of the latch type and each is providedwith the usual latch 75 pivoted to the needle at 76. The latches operatesomewhat similarly to latches found in usual knitting needles in thatthey will be moved to the left from the position shown in Fig. 9 by thepreviously formed loop as the needle is withdrawn from the web and indoing so will close the hook 70 and permit the group of fibers caught byit to be drawn through the previously formed loop.

The operation thus far described will produce a fabric such as shown inFigs. l and 5. If it is desired to form the fabric F2 suggested in Fig.6 the web can then be inverted and run through the machine again so thatthe previously formed wales will be moved along the table or plate 11and another series of wales 7 produced on the opposite side of the web.l

The previously mentioned gearing G has been omitted from Fig. 7 for thesake of clarity but is shown in Fig. 10. The bevel gear 26 meshes with abevel pinion 80 on an upright shaft 81 the lower end of which hassecured thereto another bevel pinion 82 which meshes with a bevel gearS3 on a horizontal shaft 84. A worm 85 on shaft 84 meshes with a wormgear 86 on shaft 45. The gearing G effects a considerable reduction inspeed from shaft 25 to shaft 45, and the diameters of the gears, pinionsand rolls 13, and the reduction effected by the worm, are chosen toproduce a slow forward feed of the web while permitting a high rate ofneedle operation.

Any' other suitable speed reducing mechanism can be used so long as iteffects the general result suggested by Fig 10.

In the fabrics thus far described the wales of interconnected loops areeither on one or both sides of the finished fabric but it may bedesirable in some instances to employ the principles of the invention toproduce a fabric in which the reenforcing wales are buried within thefabric so that each side of the latter has a soft fleecelike texture.This modification of the invention is illustrated in Fig. ll whereinwebs W2 and W3 similar to web W are trained respectively around rotatingdrums 90 and 91 which are turned in opposite directions by appropriatedrive means to feed the webs W2 and W3 downwardly and into face to facecontact with each other as shown in Fig. 1-1. Knitting needles N1 whichare employed in this form of the invention may be similar to thosealready described but preferably have their lower ends pointed as at 92,the Shanks 93 of the modified needles moving in a plane parallel to thatindicated by line 94 which is tangent to the contacting faces of thewebs W2 and W3 and bisects the angle between them. The point 92 may beoffset to the right of line 94 so that as the needles N1 are projecteddownwardly a part at least of the web W3 will be deliected to the leftwhere it will be ultimately picked up by the hook 95 of the needles onwithdrawal of Ithe latter. The left-hand end of the hook 95 preferablyextends to the left of line 94 so that upon full insertion of the needledown at least to the nip between the two rolls and 91, and preferablybeyond the nip, some fibers of each of the two webs W2 and W3 will bedefiected to the left and then will tend to move to the right to be overthe hook 95. In this way fibers from both of the Webs W2 and W3 will becollected by each needle to form a group of fibers which will result inloops as the needles N1 are reciprocated.

The lower part of Fig. ll shows the finished product or fabric F3wherein the wales 96 formed as described are intermediate the right sideof web W3 and the left side of web W2, thus exposing soft fleece-liketextured surfaces on both sides of the fabric. Mechanisms similar tothose shown in Fig. 7 can be employed to reciprocate the needles N1 anddrive the drums 90 and 91.

From the foregoing it will be seen that the invention sets forth simplemeans by which bers of a web are caught into small groups and areknitted together to form interconnected loops running lengthwise of theweb. In fabric F1 the loops form wales on one side of the fabric but thefibers forming the loops extend down into and are dispersed through androoted into the web in a manner quite unlike the interlocking of threadsor yarns as encountered in the usual knitting operation. The fabric thusproduced will have a knitted texture on one side of a fieece-liketexture on the opposite side, but if desired both sides of the web canbe formed with wales to form fabric F2. It will also be seen thatprovision is made for permitting the hooks to lift only those parts ofthe fibers engaged with them which `are between discs 51 and are forwardof the feet 66. It will further be seen that provision is made fordepressing the needles after they have been inserted into the web forthe purpose of reducing the numbers `of fibers which the hook will liftwhen the needles are withdrawn from the web. The in- Vention also setsforth an improved method for producing a nonwoven fabric from a web ofrandom or oriented loosely assembled fibers or textile material orelements wherein some of the latter are formed into loops which areknitted together in loops to form wales. It will be further noted thatthe fabric F3 is produced by loops the fibers of which are drawn fromeach of the two webs W2 and W3.

Having now particularly described and ascertained the nature of theinvention and in what manner the same is to be performed, what isclaimed is:

l. The method of forming a nonwoven fabric from two webs of looselyassembled textile fibers consisting n the following steps: feeding thetwo webs into face to face engagement with each other in a manner toform a nip therebetween, gathering fibers beyond the nip to be drawnfrom both webs into a group, some of the fibers of which are rooted intoone web and other fibers of which are rooted into the other web, and:forming successive groups thus formed into interconnected knittedloops.

2. The method set forth in claim 1 wherein the knitted loops are formedby a needle which is inserted between Athe nip into and parallel to bothwebs to hook onto fibers of each web and is then withdrawn to liftfibers from each web into a group from which the loop is formed.

3. The method set forth in claim 2 wherein the needle has a pointedinserting end and a hook at one side of the pointed end and the needleis inserted substantially parallel to each of said faces so that itspointed end enters one of the webs adjacent said nip to enable the hookto collect some of the fibers of that web and the hook upon withdrawalof the needle lifts fibers from the other web.

(References on following page) Rfrences cited in ne fue of this paient'UNITED STATES PATENTS Maussner Oct. 27, 1903 Billington Sept. 2, 1919 5Farr Mar. 23, 1920

1. THE METHOD OF FORMING NONWOVEN FABRIC FROM TWO WEBS OF LOOSELY ASSEMBLED TEXTILE FIBERS CONSISTING IN THE FOLLOWING STEPS: FEEDING THE TWO WEBS INTO FACE TO FACE ENGAGEMENT WITH EACH OTHER IN A MANNER TO FORM A NIP THEREBETWEEN, GATHERING FIBERS BEYOND THE NIP TO BE DRAWN FROM BOTH WEBS INTO A GROUP, SOME OF THE FIBERS OF WHICH ARE ROOTED INTO ONE WEB AND OTHER FIBERS OF WHICH ARE ROOTED INTO THE OTHER WEB, AND FORMING SUCCESSIVE GROUPS THUS FORMED INTO INTERCONNECTED KNITTED LOOPS. 